6,255 research outputs found

    Optical stark effect in the 2-photon spectrum of NO

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    A large optical Stark effect has been observed in the two-photon spectrum X(2)Pi yields A(2)Sigma(+)_ in NO. It is explained as a near-resonant process in which the upper state of the two-photon transition is perturbed by interactions with higher-lying electronic states coupled by the laser field. A theoretical analysis is presented along with coupling parameters determined from ab initio wave functions. The synthetic spectrum reproduces the major experimental features

    (2+1) resonant enhanced multiphoton ionization of H_2 via the E, F^(1)Σ^+_g state

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    In this paper, we report the results of ab initio calculations of photoelectron angular distributions and vibrational branching ratios for the (2+1) REMPI of H_2 via the E, F^(1)Σ^+_g state, and compare these with the experimental data of Anderson et al. [Chem. Phys. Lett. 105, 22 (1984)]. These results show that the observed non‐Franck–Condon behavior is predominantly due to the R dependence of the transition matrix elements, and to a lesser degree to the energy dependence. This work presents the first molecular REMPI study employing a correlated wave function to describe the Rydberg–valence mixing in the resonant intermediate state

    Automatically Generating Natural Language Descriptions of Images by a Deep Hierarchical Framework.

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    Automatically generating an accurate and meaningful description of an image is very challenging. However, the recent scheme of generating an image caption by maximizing the likelihood of target sentences lacks the capacity of recognizing the human-object interaction (HOI) and semantic relationship between HOIs and scenes, which are the essential parts of an image caption. This article proposes a novel two-phase framework to generate an image caption by addressing the above challenges: 1) a hybrid deep learning and 2) an image description generation. In the hybrid deep-learning phase, a novel factored three-way interaction machine was proposed to learn the relational features of the human-object pairs hierarchically. In this way, the image recognition problem is transformed into a latent structured labeling task. In the image description generation phase, a lexicalized probabilistic context-free tree growing scheme is innovatively integrated with a description generator to transform the descriptions generation task into a syntactic-tree generation process. Extensively comparing state-of-the-art image captioning methods on benchmark datasets, we demonstrated that our proposed framework outperformed the existing captioning methods in different ways, such as significantly improving the performance of the HOI and relationships between HOIs and scenes (RHIS) predictions, and quality of generated image captions in a semantically and structurally coherent manner.\enlargethispage-8pt

    Parent training for preschool ADHD: a randomized controlled trial of specialized and generic programs

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    BackgroundThe New Forest Parenting Package' (NFPP), an 8-week home-based intervention for parents of preschoolers with attention-deficit/hyperactivity disorder (ADHD), fosters constructive parenting to target ADHD-related dysfunctions in attention and impulse control. Although NFPP has improved parent and laboratory measures of ADHD in community samples of children with ADHD-like problems, its efficacy in a clinical sample, and relative to an active treatment comparator, is unknown. The aims are to evaluate the short- and long-term efficacy and generalization effects of NFPP compared to an established clinic-based parenting intervention for treating noncompliant behavior [Helping the Noncompliant Child' (HNC)] in young children with ADHD. MethodsA randomized controlled trial with three parallel arms was the design for this study. A total of 164 3-4-year-olds, 73.8% male, meeting DSM-IV ADHD diagnostic criteria were randomized to NFPP (N=67), HNC (N=63), or wait-list control (WL, N=34). All participants were assessed at post-treatment. NFPP and HNC participants were assessed at follow-up in the next school year. Primary outcomes were ADHD ratings by teachers blind to and uninvolved in treatment, and by parents. Secondary ADHD outcomes included clinician assessments, and laboratory measures of on-task behavior and delay of gratification. Other outcomes included parent and teacher ratings of oppositional behavior, and parenting measures. (Trial name: Home-Based Parent Training in ADHD Preschoolers; Registry: ClinicalTrials.gov Identifier: NCT01320098; URL: ). ResultsIn both treatment groups, children's ADHD and ODD behaviors, as well as aspects of parenting, were rated improved by parents at the end of treatment compared to controls. Most of these gains in the children's behavior and in some parenting practices were sustained at follow-up. However, these parent-reported improvements were not corroborated by teacher ratings or objective observations. NFPP was not significantly better, and on a few outcomes significantly less effective, than HNC. ConclusionsThe results do not support the claim that NFPP addresses putative dysfunctions underlying ADHD, bringing about generalized change in ADHD, and its underpinning self-regulatory processes. The findings support documented difficulties in achieving generalization across nontargeted settings, and the importance of using blinded measures to provide meaningful assessments of treatment effects

    Peierls distorted chain as a quantum data bus for quantum state transfer

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    We systematically study the transfer of quantum state of electron spin as the flying qubit along a half-filled Peierls distorted tight-binding chain described by the Su-Schrieffer-Heeger (SSH) model, which behaves as a quantum data bus. This enables a novel physical mechanism for quantum communication with always-on interaction: the effective hopping of the spin carrier between sites AA and BB connected to two sites in this SSH chain can be induced by the quasi-excitations of the SSH model. As we prove, it is the Peierls energy gap of the SSH quasi-excitations that plays a crucial role to protect the robustness of the quantum state transfer process. Moreover, our observation also indicates that such a scheme can also be employed to explore the intrinsic property of the quantum system.Comment: 10 pages, 6 figure

    Cross sections for excitation of the b3Σu+, a3Σg+, and c3Πu states of H2 by low-energy electrons

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    We used a multichannel extension of the Schwinger variational principle [K. Takatsuka and V. McKoy, Phys. Rev. A 24, 2473 (1981)] to study the cross sections for excitation of the X 1 Σg+→b 3Σu+, a 3Σg+, and c3Πu transitions in H2 by low-energy electrons. These cross sections were obtained with two open channels for each transition and for energies near threshold to 30 eV. The results for the b3Σu+ and a 3Σg+ states agree quite well with available experimental data. However, the cross sections for excitation of the c 3Πu state differ significantly from the measured values at the two energies, 20 and 30 eV, where data are available

    HST and LAMOST discover a dual active galactic nucleus in J0038+4128

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    We report the discovery of a kiloparsec-scale dual active galactic nucleus (AGN) in J0038+4128. From the Hubble Space Telescope (HST) Wide Field Planetary Camera (WFPC2) images, we find two optical nuclei with a projection separation of 4.7 kpc (3.44 arcsec). The southern component (J0038+4128S) is spectroscopically observed with the HST Goddard High Resolution Spectrograph in the UV range and is found to be a Seyfert 1 galaxy with a broad Ly alpha emission line. The northern component (J0038+4128N) is spectroscopically observed during the Large Sky Area Multi-Object Fibre Spectroscopic Telescope (also named the Guoshoujing Telescope) pilot survey in the optical range. The observed line ratios as well as the consistency of redshift of the nucleus emission lines and the host galaxy's absorption lines indicate that J0038+4128N is a Seyfert 2 galaxy with narrow lines only. These results thus confirm that J0038+4128 is a Seyfert 1-Seyfert 2 AGN pair. The HST WFPC2 F336W/U-band image of J0038+4128 also reveals for the first time for a dual AGN system two pairs of bi-symmetric arms, as are expected from the numerical simulations of such system. Being one of a few confirmed kiloparsec-scale dual AGNs exhibiting a clear morphological structure of the host galaxies, J0038+4128 provides an unique opportunity to study the co-evolution of the host galaxies and their central supermassive black holes undergoing a merging process.Comment: 6 pages, 4 figures, 2 tables, Accepted for publication in MNRAS Letter

    Graphene-based hybrid plasmonic waveguide for highly efficient broadband mid-infrared propagation and modulation

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    © 2018 Optical Society of America. In this paper, a graphene-based hybrid plasmonic waveguide is proposed for highly efficient broadband surface plasmon polariton (SPP) propagation and modulation at mid-infrared (mid-IR) spectrum. The hybrid plasmonic waveguide is composed of a monolayer graphene sheet in the center, a polysilicon gating layer, and two inner dielectric buffer layers and two outer parabolic-ridged silicon substrates symmetrically placed on both sides of the graphene. Owing to the unique parabolic-ridged waveguide structure, the light-graphene interaction and subwavelength SPPs confinement of the fundamental SPP mode for the hybrid waveguide can be significantly increased. Under the graphene chemical potential of 1.0 eV, the proposed waveguide can achieve outstanding SPP propagation performance with long propagation length of 12.1-16.7 μm and small normalized mode area of ~10−4 in the frequency range of 10-20 THz, exhibiting more than one order smaller in the normalized mode area while remaining the propagation length almost the same level with respect to the hybrid plasmonic waveguide without parabolic ridges. By tuning the graphene chemical potential from 0.1 to 1.0 eV, we demonstrate the waveguide has a modulation depth greater than 51% for the frequency ranging from 10 to 20 THz and reaches a maximum of nearly 100% at the frequency higher than 18 THz. Benefitting from the excellent broadband mid-IR propagation and modulation performance, the graphene-based hybrid plasmonic waveguide may open up a new way for various mid-IR waveguides, modulators, interconnects and optoelectronic devices

    Studies of electron–polyatomic-molecule collisions: Applications to e-CH4

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    We report the first application of the Schwinger multichannel formulation to low-energy electron collisions with a nonlinear polyatomic target. Integral and differential cross sections are obtained for e-CH4 collisions from 3 to 20 eV at the static-plus-exchange interaction level. In these studies the exchange potential is directly evaluated and not approximated by local models. An interesting feature of the small-angle differential cross section is ascribed to polarization effects and not reproduced at the static-plus-exchange level. Our differential cross sections are found to be in reasonable agreement with existing measurements at 7.5 eV and higher energies
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